Belgian Biomass Workshop in the frame of BERA/EERA, Louvain-la-Neuve, Belgium, 27-28 August 2012

Abstract:

The Belgian Campine has long been the subject of multidisciplinary research into phytoremediation
of a vast area of farmland that has been moderately polluted with heavy metals such as cadmium.
On an experimental field in the municipality of Lommel biologists have been investigating the metal
extraction potential of energy maize, rapeseed and short rotation coppice amongst others. Especially
willow demonstrated some phytoextracting capacity whereas the metal extraction potential of
energy maize appeared to be rather limited. From an economic point of view however, energy maize
is a feasible option for generating an alternative income for the affected farmers whereas the
economic potential of willow has been open for further investigation. Because willow mainly consists
of lignin, cellulosis and hemicellulosis, thermochemical technologies are better suited than biological
ones for the conversion of willow into valuable products. Fast pyrolysis appears to be more
promising than combustion and gasification both from an ecological and an economical point of
view. Due to the lower process temperature of fast pyrolysis most of the metals do not volatilize and
remain in the residual char. For the small scale of operation expected in the Belgian Campine, fast
pyrolysis is also preferred above combustion and gasification in terms of return on investment.
However, economic risk analysis showed that even with fast pyrolysis there is a high chance of
economic loss. Therefore risk reduction strategies have been identified: combined production of heat
and power, fast co-pyrolysis of willow with biopolymers, and activation of the residual char show
promising results.